Well-Controlled Cell-Trapping Systems for Investigating Heterogeneous Cell–Cell Interactions

Microfluidic systems have been developed for patterning single cells to study cell–cell interactions. However, patterning multiple types of cells to understand heterogeneous cell–cell interactions remains difficult. Here, it is aimed to develop a cell-trapping device to assemble multiple types of cells in the well-controlled order and morphology. This device mainly comprises a parylene sheet for assembling cells and a microcomb for controlling the cell-trapping area. The cell-trapping area is controlled by moving the parylene sheet on an SU-8 microcomb using tweezers. Gentle downward flow is used as a driving force for the cell-trapping. The assembly of cells on a parylene sheet with round and line-shaped apertures is demonstrated. The cell–cell contacts of the trapped cells are then investigated by direct cell–cell transfer of calcein via connexin nanopores. Finally, using the device with a system for controlling the cell-trapping area, three different types of cells in the well-controlled order are assembled. The correct cell order rate obtained using the device is 27.9%, which is higher than that obtained without the sliding parylene system (0.74%). Furthermore, the occurrence of cell–cell contact between the three cell types assembled is verified. This cell-patterning device will be a useful tool for investigating heterogeneous cell–cell interactions.